1. Field of the Invention
The present invention relates to an etching apparatus for fabricating a semiconductor device, and more particularly, to a surface wave coupled plasma etching apparatus.
2. Description of the Related Art
As semiconductor wafers become larger, there has been an increasing need for semiconductor fabrication apparatuses capable of processing the large wafers. Particularly, an etching apparatus capable of forming a plasma over a large area is required to form uniform fine patterns having critical dimensions on the wafer.
A surface wave coupled plasma etching apparatus, which is disclosed in "Oxide etching using surface wave coupled plasma", Jpn. J. Appl. Phys. Vol. 33 (1994) pp. 7037-7041, by Takeshi Akimoto, Eiji Ikawa, Toshiaki Sango, Kyouichi Komachi, Katuo Katayama and Tosiki Ebata, is proposed to provide uniform plasma etching of large wafers. The surface wave coupled plasma etching apparatus uniformly generates a plasma over a large area by a microwave (2.45 GHz) excitation. The microwave is introduced into the surface wave coupled plasma etching apparatus through a dielectric plate, for instance, a polymer plate into an etching chamber confined by a grounded metal, upper electrode.
A conventional surface wave coupled plasma etching apparatus typically applies a high power radio frequency signal to a lower electrode, and thus the plasma etches the upper metal electrode as well as the semiconductor wafer. Accordingly, metal particles from the upper metal electrode contaminate the semiconductor wafer and can cause a failure of the semiconductor wafer etching.